Start by adding cranberry juice, tinned cherries, and caster sugar into a saucepan. Bring it to a gentle boil, then reduce to a simmer until it thickens and reduces by half. Allow it to cool before using. This syrup gives the margarita its deep festive color and fruity sweetness.
In a cocktail jug or shaker, combine the Anejo tequila, Cointreau, lime juice, spiced ginger beer, and the cooled cranberry-cherry syrup. Stir well to combine but don’t shake too hard—this helps preserve the fizz of the ginger beer.
Pour your margarita into a chilled glass. For that wow factor, garnish with a mix of meringue kisses, mint leaves, and fresh berries. The contrast of colors and textures makes it look like a drink straight out of a holiday dream.